Phase Separation-based Antiviral Decoy Particles as Basis for Programmable Broad-spectrum Therapeutics

To gain access to cells, viruses employ host proteins as receptors. In soluble form, these receptors are used as decoys to inhibit infection. We fused candidate soluble receptors to an RNA-binding protein, and using synthetic long non-coding RNA (slncRNA) cassettes that can undergo phase-separation we scaffolded the receptor fusions to generate antiviral decoy particles. Using confocal microscopy, we screened antiviral protein candidates by observing changes in phase-separation morphology when incubated with viral-mimicking components. We demonstrated that ACE2 decoy particles bind strongly to the coronavirus RBD, facilitating FRET, while sufficiently sialylated decoy particles form agglutinated structures with RNA peripheries in the presence of a sialolectin. Infection assays show ACE2 decoy particles fully inhibit the Delta and Omicron BA.1 coronavirus variants, and LAMP1 and GYPA decoy particles significantly reduce influenza infection in-cellulo. This work establishes a foundation for broad-spectrum antiviral decoy particles, composed of multiple receptors targeting various viruses.